Trihalomethanes formation potential of polluted tropical river water and its correlation with UV-Vis spectral ratio: A case study in Citarum River, Indonesia

Abstract

The presence of natural organic matter (NOM) and anthropogenic organic matter (AOM) in polluted river water leads to the formation of carcinogenic disinfection by-products (DBPs) during the water chlorination process. This study aimed to determine trihalomethanes (THMs) formation, as the regulated DBPs, in polluted tropical river water. The samples were taken from the Citarum River, Bandung, Indonesia. The NOM and AOM were characterized using UV254, UV355, and ultraviolet-visible (UV-Vis) spectral ratio while DBPs formation was determined using THM4 formation potential. In several sampling points, the THM4 formation potential of the samples exceeded the USEPA regulation standards and had high toxicity (LC50) values. On the other hand, other sampling points had small THM4 formations. Also, the THM4 formation potential was found to have a great correlation with the spectral ratio, especially A280/A350 UV absorbances that could be further used as a surrogate parameter of THM4 formation. Citarum River, as a water source, needs sufficient treatment to remove the DBPs precursors to provide healthy and clean potable water.